U.S. patent application number 10/132710 was filed with the patent office on 2002-11-28 for spindlehead for tools.
This patent application is currently assigned to Sauter Feinmechanik GmbH.. Invention is credited to Sahm, Detlef, Wezel, Rolf.
Application Number | 20020176758 10/132710 |
Document ID | / |
Family ID | 7683603 |
Filed Date | 2002-11-28 |
United States Patent
Application |
20020176758 |
Kind Code |
A1 |
Sahm, Detlef ; et
al. |
November 28, 2002 |
Spindlehead for tools
Abstract
The invention relates to a spindlehead for tools which may be
inserted into a tool disk with holders provided for this purpose
and whose chucking means for spindle (10) holding the shank of the
tool is rotatably mounted in a second section (26) adjacent to the
first end section (12) receiving the tool shank, with a spindle
bearing (14), and with a coolant feed (34) guided at least in part
in the spindlehead housing (16), coolant transfer for the
respective tool being effected by way of at least one coolant
channel (40, 42, 44) which applies an internal coolant feed (34)
for the respective tool by way of a sealing device (52) with
throttling point separated from parts of a drainage channel (46,
48, 50) and the sealing device (52) having at least one seal (54,
56) which encloses the spindle (10). In that the respective sealing
ring (54, 56) is introduced into the spindlehead housing (16) so as
to be longitudinally movable coaxially with the spindle axis (58),
and in that, after longitudinal movement into a sealing position,
the respective sealing ring (54, 56) separates the internal coolant
feed (34) from the parts of the drainage channel (46, 48, 50) which
may be associated with it, up to a leakage amount which may be
specified, the accuracy of machining with the tool may be increased
and the installation space available can be better used.
Inventors: |
Sahm, Detlef; (Lichtenwald,
DE) ; Wezel, Rolf; (Metzingen, DE) |
Correspondence
Address: |
ROYLANCE, ABRAMS, BERDO & GOODMAN, L.L.P.
1300 19TH STREET, N.W.
SUITE 600
WASHINGTON,
DC
20036
US
|
Assignee: |
Sauter Feinmechanik GmbH.
|
Family ID: |
7683603 |
Appl. No.: |
10/132710 |
Filed: |
April 26, 2002 |
Current U.S.
Class: |
409/231 ;
409/136; 82/159 |
Current CPC
Class: |
Y10T 409/304032
20150115; Y10T 408/44 20150115; Y10T 409/303976 20150115; B23Q
11/1023 20130101; Y10T 82/2587 20150115; Y10T 409/309296 20150115;
B23Q 1/0036 20130101; Y10T 409/309352 20150115 |
Class at
Publication: |
409/231 ;
82/159 |
International
Class: |
B23C 007/02; B23C
005/28 |
Foreign Application Data
Date |
Code |
Application Number |
May 2, 2001 |
DE |
101 21 694.7 |
Claims
1. A spindlehead for tools which may be inserted into a tool disk
with holders provided for this purpose and whose chucking means for
the spindle (10) holding the shank of the tool is rotatably mounted
in a second section (26) adjacent to the first end section (12)
receiving the tool shank, with a spindle bearing (14), and with a
coolant feed line (34) guided at least in part in the spindlehead
housing (16), coolant transfer for the respective tool being
effected by way of at least one coolant channel (40, 42, 44) which
applies an internal coolant feed (34) to the respective tool by way
of a sealing device (52) with throttling point separated from parts
of a drainage channel (46, 48, 50) and the sealing device (52)
having at least one seal (54, 56) which encloses the spindle (10),
characterized in that the respective sealing ring (54, 56) is
introduced into the spindlehead housing (16) so as to be
longitudinally movable coaxially with the spindle axis (58), and in
that, after longitudinal movement into a sealing position, the
respective sealing ring (54, 56) separates the coolant feed (34)
from the parts of the drainage channel (46, 48, 50) which may be
associated with it, up to a leakage amount which may be
specified.
2. The spindlehead as specified in claim 1, wherein the sealing
device (52) has two sealing rings (54, 56) the sealing surfaces of
which are positioned opposite the spindlehead housing (16) on the
front sides facing away from each other.
3. The spindlehead as specified in claim 2, wherein the two sealing
rings (54, 56) are connected to the coolant feed on their sides
(60) facing each other.
4. The spindlehead as specified in claim 2 or 3, wherein each
sealing ring (54, 56) has on its external circumference an elastic
sealing means (70) which, resting on the spindlehead housing (16),
exerts a restoring force on the sealing rings (54, 56) which tends
to hold such rings together.
5. The spindlehead as specified in one of claims 2 to 4, wherein
the throttling point for the sealing rings (54, 56) is in the form
of lubricant pouches (72) which form a leakage point on their front
on the separated limiting surfaces (74) of the sealing rings (54,
56) for passage of coolant.
6. The spindlehead as specified in claim 5, wherein the respective
leakage point discharges into the drainage channel (46, 48, 50),
which extends to the exterior from the spindlehead housing (16), at
least on the tool side.
7. The spindlehead as specified in one of claims 1 to 6, wherein
the sealing device (52) encloses the spindle (10) on the side
facing away from the tool shank and beyond the engaging spindle
bearing (14) on the first end section (12).
8. The spindlehead as specified in one of claims 1 to 7, wherein
additional seals (80, 84) are present in the longitudinal direction
of the spindle (10) upstream and downstream from the sealing device
(52), and wherein one of these additional seals (84) seals the
spindle bearing (14) from the sealing device (52).
9. The spindlehead as specified in one of claims 1 to 8, wherein
the sealing device (52) also makes dry operation without coolant
possible for tool machining.
10. The spindlehead as specified in one of claims 1 to 9, wherein
the coolant feed (40), emerging radially from the spindlehead
housing (16), may be connected to a central supply source or to a
pinhole (30).
Description
[0001] The invention relates to a spindlehead for tools which may
be inserted into a tool disk with tool carriers provided for this
purpose and to chucking means for the spindle holding the shank of
the tool in a second end section adjoining the first end section
rotatably mounted in the spindlehead housing, with a spindle
bearing and with a coolant feed line guided at least in part in the
spindlehead housing, the coolant being transferred over at least
one coolant channel which represents an internal coolant feed line
for the tool involved, the internal coolant feed line being
separated from a drainage channel by way of a sealing device with
throttle point, and the sealing device having at least one sealing
ring which encloses the spindle.
[0002] DE 195 16 986 C2 discloses a spindlehead for tools which may
be inserted into a tool disk of a turret with tool insertion holes
as specified in DIN 69880 [German Industrial Standard 69880]
(especially Part 6, March 2000, pages 2 and 4).
[0003] In addition, coolant transfer occurs in a spindlehead cover
provided on the tool side in which an annular groove is provided,
into which a coolant feed channel discharges, over which channel
coolant is delivered internally for a particular tool. In the
conventional solution the coolant transfer point is situated
upstream from the spindle bearing and the annular groove is open up
to the first end section and is provided with a connecting channel
one end of which discharges into the annular zone of the first end
zone surface oriented toward the annular groove and the other end
of which discharges into a chucking means space of the spindle with
which the inlet opening provided in the shank end of the coolant
channel extending through the tool communicates. The annular groove
itself is sealed from the exterior by an external split seal and
from the interior in the direction of the spindle bearing by an
internal split seal; both the external and the internal split seals
are bounded by the external surface of the spindle and the internal
surface of the spindlehead. This arrangement results in a creation
of a spindlehead for tools with internal coolant feed which takes
up little installation space on the tool disk. In addition,
reliable sealing is ensured which in no way exposes the spindle
bearing to damage by the coolant.
[0004] DE 38 24 427 A1 discloses a machine tool with a spindlehead
carrier and a spindlehead mounted on this carrier and provided with
a spindle. The drive shaft mounted in the spindlehead carrier is
connected to the spindle by way of gears, bevel gears in
particular. In the area of the gears an oil circulation space for
lubrication of the gears is provided which is sealed from the
stationary component of the spindlehead by sealing elements to
which compressed air is applied by way of compressed air feed lines
which feed compressed air by way of throttling ports to the front
sealing surfaces of the sealing elements operating in conjunction
with opposite rotating sealing surfaces. The pressure relationships
and the line cross-sections selected are such that a sealing gap is
present for the purpose of contact-free sealing between the
rotating opposite sealing surfaces and the sealing surfaces of the
sealing elements. Hence the conventional solution achieves oil
lubrication through an oil circulation space; escape of oil at an
undesirable location is prevented by sealing of the oil circulation
space by compressed air. The compressed air introduced into the oil
circulation space and the resulting excess pressure make certain
that the oil lubricant will reach the gears to be lubricated; the
oil circulation space is then filled with an oil and air mixture
and the gears need not operate entirely in oil. The sealing gap in
question of the respective sealing elements thus serves the purpose
of delivery of lubricant for the gearing referred to.
[0005] DE 42 26 922 A1 discloses a generic spindlehead having a
coolant device for supply of the respective boring and/or cutting
tools with coolant and/or lubricant; the spindle is provided with
an axial channel element fed by way of an opening in a stationary
feed device for transfer of the coolant and/or lubricant to the
tool/working area and the feed device and the spindle mesh to form
a split seal coaxially. In the conventional solution leaks through
the split seal are removed by way of a pressure relief space so as
to flow to the exterior (virtually free of pressure) and this
pressure relief space is sealed from the spindlehead housing
downstream on the bearing side by another split seal. The coolant
feed proper further requires delivery of compressed air for the
conventional sealing solution; compressed air is applied to this
split seal to support the sealing effect. The respective
conventional solution in this embodiment requires much installation
space and is cost-intensive in application and in maintenance.
[0006] With this state of the art taken as a basis, the object of
the invention is further to optimize the conventional spindlehead
solutions, and in particular to increase the accuracy of machining
with the tool, achieve better use of available installation space,
and lower manufacturing costs and potential maintenance costs. The
object as formulated in these terms is attained by means of a
spindlehead having the features specified in claim 1 in its
entirety.
[0007] In that, as specified in the descriptive portion of claim 1,
the respective sealing ring is guided coaxially and longitudinally
so as to be displaceable with the spindle axis in the spindlehead
housing and in that, after longitudinal displacement into a sealing
position, the respective sealing ring separates the interior
coolant feed, including a prescribable leakage amount, from the
parts of the drain channel to be associated with the feed, the
interior coolant feed from the area of the pressurized means for
the shank of the tool may be transferred back in the opposite
direction into the spindlehead housing, with the result that the
spindle bearing itself can move further forward into the area of
the pressurized means, so that the tool is better guided and
supported by way of the spindle carrier and the spindle bearing,
this being a situation which definitely favors machining
accuracy.
[0008] Since the internal coolant feed may now take place
exclusively centrally by way of the sealing device and along the
longitudinal axis of the spindle, installation space is conserved
and, in addition, a cost-effective solution is achieved, one which
also noticeably lowers any subsequent maintenance costs.
[0009] Since the respective sealing ring of the sealing device may
be displaced longitudinally, a kind of dynamic sealing is achieved
which is automatically adapted to prescribed machining situations
such as delivery of coolant lubricants, speed of spindle unit, etc.
Because of the floating layout of the respective sealing ring,
sealing is effected as a function of the pressure relationships and
the quantity of coolant to be supplied, with the result that the
optionally aggressive coolant cannot reach places which might be
damaged by it, ones in the form of the spindle bearing, for
example.
[0010] In a preferred embodiment of the spindlehead claimed for the
invention, the sealing device has two sealing rings whose sealing
surfaces are positioned opposite the spindlehead housing with their
front sides facing away from each other. This permits a layout in
which the respective sealing ring is guided over the external
circumference along the spindlehead housing and can slide,
generating little friction, on a cushion of coolant which produces
internal feed of coolant over the spacing between the respective
sealing ring and spindle. Sealing with a prescribed amount of
leakage can then be effected by way of the front side of the
sealing ring in question facing the spindlehead housing.
[0011] In another preferred embodiment of the spindlehead claimed
for the invention the two sealing rings are connected to the
coolant feed line on their sides facing each other, and axially
there is present in the spindle an optional connection for internal
coolant feed. This results in good control of the sealing rings by
way of the coolant, as well as in the need for less installation
space as a result of intervention of the internal coolant feed in
the connection option, with the result that space is conserved.
[0012] In an especially preferred embodiment of the spindlehead
claimed for the invention, each sealing ring has flexible sealing
means on its external circumference, means which, resting on the
spindlehead housing, exert a restoring force on the sealing rings
which tends to keep the rings together. Dry operation of the
spindlehead without coolant is also possible on the basis of this
layout. The two sealing rings are held together and kept at a
distance from the driven spindle both axially and radially so that
to this extent no harmful friction occurs and the spindle can
rotate freely in the spindle bearing.
[0013] In another preferred embodiment of the spindlehead claimed
for the invention, the throttling point is in the case of the
sealing rings in the form of lubricant pouches which, being mounted
spaced at a distance from each other on the limiting surface of the
sealing rings to allow passage of coolant, form a leakage point. A
small leakage flow of coolant is built up by way of the lubricant
pouches in question, but this flow is in the form of a pressure
cushion such that the rotating spindle moves more or less free of
friction inside the sealing rings mounted stationarily in the
spindlehead housing. A sort of hydrostatic lubrication is thereby
achieved. The respective leakage point discharges preferably into
the drainage channel, which emerges from the spindlehead housing
into the open by way of a longitudinal channel section extending
parallel to the longitudinal axis of the spindle.
[0014] In a preferred embodiment of the spindlehead claimed for the
invention the sealing device encloses the spindle on the side
facing away from the tool shank beyond the spindle bearing engaging
the first end section. The sealing device is thus mounted between a
first and a second end section of the actuatable body of the
spindle in the spindlehead housing more or less in a manner so as
to conserve space.
[0015] In another preferred embodiment of the spindlehead claimed
for the invention, additional seals are present upstream and
downstream from the spindle in the longitudinal direction, one of
which seals the spindle from the sealing device. In this way
lubrication of the spindle by way of the leakage points is sealed
from the other parts of the spindle bearing. The layout as
described preferably also makes it possible to connect the coolant
feed radially from the spindlehead housing to a central supply
point; this also conserves space and ensures dependable coolant
supply.
[0016] The spindlehead claimed for the invention is described in
detail in what follows with reference to the drawings, in outline
and not drawn to scale,
[0017] FIG. 1 illustrates a longitudinal section through an
embodiment of the spindlehead;
[0018] FIGS. 2a, b, c presents a bottom view, side view, and top
view in the line of vision of the left sealing ring of the sealing
device shown in FIG. 1.
[0019] The spindlehead shown in FIG. 1 serves as holder of
machining tools not shown, which tools are generally displaced in
circulatory rotation for the purpose of machining. For this purpose
a spindle 10 is rotatably mounted in the area of its front end
section 12 by way of two roller bearings 14 in a spindlehead
housing 16; both the inner bushing sleeves 18 and the outer bushing
sleeves 20 of the two roller bearings are kept at a distance from
each other each by way of a spacing sleeve 22. A lock nut 24 which
may be screwed by its internal threading onto a matching external
threading on the spindle 10 serves to fasten the two roller
bearings 14 by way of their inner bearing shells 18 on the front
end section 12 of the spindle 10. The rear end section 26 of the
spindle 10 extends through a hollow shank 28 formed on the
spindlehead housing 16 and is connected to one of the front
surfaces of the latter by way of its free end. A standardized
pinhole 30 and the hollow shank 28 in question are designed so that
the latter may be introduced into a tool receptacle as specified in
DIN 69880. The geared end section 32 of the spindle 10 projecting
beyond the hollow shank 28 may be coupled with a drive shaft (not
shown) for driving the spindle 10 and accordingly the tool.
[0020] The end section 12 of the spindle 10 contains, for example,
a conventional chuck for the shank of a tool (not shown), such as
one in the form of a drill. This tool is preferably one with an
inner coolant channel. If the shank of the tool has been fully
inserted into the chuck and connected to the spindle 10 rigidly and
tightly to the chuck, the front end of an internal coolant feed
channel 34 communicates with a central chucking space 36, so that,
when a tool is inserted, a fluid conducting connection exists
between the internal coolant feed 34 and the internal coolant
channel of the tool. In this way the tool can be suitably supplied
with coolant during machining.
[0021] The coolant feed line 34 in question is part of a coolant
transmission system designated as a whole as 38 and having several
sections of coolant channels 40, 42, 44. The internal coolant
transmission system 34 with its associated channel sections 42 and
44 is in turn separated from the drainage system 46, 48, and 50 by
way of a sealing device with throttling point designated as a whole
as 52. The sealing device 52 consists essentially of two sealing
rings 54 and 56; the sealing ring 56 shown on the left in the line
of sight to FIG. 1 is illustrated in different views in FIGS. 2a,
2b, and 2c. In addition, the drainage system and thus the drainage
channel with its sections 46, 48, and 50 are under ambient
pressure.
[0022] The two sealing rings 54, 56 enclose the actuatable spindle
10 and are guided coaxially with the spindle axis 58 so as to be
displaceable longitudinally in the spindlehead housing 16. In
addition, the two sealing rings 54, 56 are connected on their sides
60 facing each other to the coolant transmission system in the form
of a coolant channel section 40. Coolant channel section 40
discharges into the connection points 62 of the respective ring 54,
56 and is connected to the interior 64 of the respective sealing
ring 54, 56 so as to conduct fluid; a radial gap 66 is maintained
while the spindle element of the spindle 10 extends through the
interior 64 in question.
[0023] The four transverse channel sections, in the form of the
channel sections 42 and 44, which extend entirely through the
spindle 10, discharge in the area on the end side into the interior
coolant feed line 34 for the tool; the coolant channels 42 and 44
extend through the spindle 10 transversely to the longitudinal
spindle axis 58, while internal coolant feed line 34 extends along
the spindle axis 58 centrally inside the spindle element. Supply of
the internal coolant feed line 34 then takes place by way of
coolant channel 40 carrying fluid, by way of the annular or radial
gap 66 referred to.
[0024] The respective sealing ring 54, 56 is provided on its
external circumference with an engagement groove 68 (FIG. 2b) in
which a conventional sealing O-ring 70 is engaged as flexible
sealing means. When the two sealing rings 54, 56 are installed,
they rest on the spindlehead housing 16 in such a way that a
restoring force is applied to the sealing rings 54, 56, a force
which tends to keep these rings together by way of the respective
side 60. The throttling point of the sealing device 52 is made up
of lubricant pouches 72 in the case of the individual sealing rings
54, 56, which pouches are in the form of recesses in the plane
frontal side 74 and form a fluid-conducting connection,
coolant-conducting in particular, in the direction of the
longitudinal spindle axis 58 with the radial gap 66 or with the
interior 64 of the respective sealing ring 54, 56.
[0025] As is to be seen especially in FIG. 2c, there are six
lubricant pouches 72 mounted diametrically opposite each other
present for a sealing ring 54, 56. The two frontal sides 74 spaced
a distance from each other form limiting surfaces, as viewed in the
line of sight to FIG. 1, the left limiting surface 74 of the
sealing ring 56 adjoins the flange-like widening of a bushing 76,
which is held in position on the second end section 26 of the
spindle 10 by a threaded element 78; the free spacing of the
sealing rings 54, 56 relative to each other and to the first end
section 12 of the spindle 10 may be adjusted by modifying the feed
travel of the bushing 76.
[0026] In addition, the bushing 76 is mounted on its external
circumference in the spindlehead housing 16 by way of another seal
80. Since the two sealing rings 54, 56 thus have prescribable play
axially between the flange-like widening of the bushing 76 and a
mounting shoulder 82 of the spindle 10, the lubricant pouches 72
form, by way of the respective limiting surface 74 of the sealing
rings 54, 56, a desirable leakage point by way of which the coolant
delivered through the radial gap 66 may be discharged into the
drainage channels 46, 48 and 50. An additional second seal 84 is
present between spindlehead housing 16 and first end section 12 of
the spindle 10 so that no coolant can move in the direction of the
spindle bearing 14 by way of the leakage point, which discharges
into the coolant channel 46.
[0027] For the sake of better understanding, the operation of the
sealing device 52 will now be described in detail on the basis of a
practical embodiment. In order to guarantee operation, first the
coolant channel section 40 is to be connected to a coolant supply
by way of the pin hole 30. Once connection has been made to the
coolant feed device 40 and suitable pressure has been built up in
the coolant channel 40, the sealing rings 54, 56 held together by
the sealing O-rings 70 are moved apart; additional fluid pressure
is built up by way of the radial gap 66 and is then established in
the lubricant pouches 72 of the limiting surfaces 74. Because of
the floating arrangement of the sealing rings 54, 56 in the
spindlehead housing 16, a dynamic equilibrium is established for
these rings and they are conducted more or less free of friction
either against each other or against the bushing 76 or the support
shoulder 82 of the spindle 10. Consequently, the spindle 10 can
transfer high speeds and torque to the machining tool without
exertion of a harmful effect on the sealing device 52.
[0028] The leakage flow of coolant referred to can be forwarded by
way of drainage channel sections 46, 48, and 50 and from their
discharged into the open. Additional longitudinal coolant channels
(not shown) may be present in order to feed large amounts of
coolant under pressure directly to the tool from the exterior. If
the coolant feed over channel 40 is interrupted, the two sealing
O-rings 70 force the sealing rings 54, 56 back and, in addition to
the radial gap 66, an axial gap is formed between the respective
limiting surfaces 74 and the facing sides of bushing 76 and bearing
shoulder 82 of the spindle 10. In this configuration it would then
also be possible to carry out dry machining with the spindlehead,
since the spindle 10 is in such a case controlled so as to be free
of contact in the sealing rings 52, 54. A process of hydrostatic
lubrication is otherwise accomplished with the layout referred
to.
[0029] Since all the sealing systems are mounted behind the spindle
bearing 14, the latter may be mounted far forward in the
spindlehead housing 16 in the direction of the tool holding
fixture. Consequently, the first or front end section 12 of the
spindle 10 moves in the area of engagement of the tool; this
permits high machining accuracy with the tool. Release of the cover
element 86 of the spindlehead housing 16 also permits immediate
access to the bearing points, this being advantageous especially in
assembly and maintenance operations. The cover element itself is
provided with a sealing unit 88 which seals the interior of the
spindle bearing 14 from the exterior, the sealing unit 88 in turn
enclosing the spindle 10 radially from the exterior on its front
end.
[0030] The sealing device 52 is in the form of a kind of plane
seal; as viewed in the longitudinal direction this results in very
short installation lengths for the spindlehead.
* * * * *